Blown controller on Totem CS-240

[cwc]

First, If I am asking these questions in the wrong place I would appreciate suggestions of other places to ask them.

The subject bike belongs to a neighbor lady who asked me to take a look at it with the complaint that it didn't seem to be providing any assist when pedaling.
When she brought it to me the display/throttle assembly would not display anything so I disconnected the large red wire from the battery to check the voltage. The voltage was ~37 volts.
When I attempted to reconnect the wire there was an arc that would have made an arcwelder proud and which damaged both halves of the connection.
The red wire going into the controller is now a dead short to ground.
This disconnect and connection occurred within just a few minutes and no other things were done to the controller between connect and disconnect.

I can buy another controller for about USD 40 but I'm concerned that other damage was done.

I've looked at circuits and block diagrams of similar controllers and it appears that there is an internal regulator to supply the various sensors etc that should probably protect these external devices. If I'm lucky.

Can anybody shed more light on this subject?

 

[indianajo]

That controller has a bad case of moisture damage. Probable an internal short on a board surface. Replace it.
You should match the intended voltage and approximate the current rating. As 36 v 14 A. Slightly larger current is okay, but I would not go over 22 A. Many replacement controllers are 36/48 v. The processor senses the start voltage at power up. I buy controllers on ebay.
The most important parameter to match on a controller is the type connectors it uses. There are white square hall effect ones and instead round juli hall effect ones. The round ones are have the motor phase wires built into the Juli connector. If the phase wires are spade lugs instead of 4 mm bullet connectors, you can install conversion wires. I put the spade lugs on a screw terminal board mounted near the controller.
Some throttles, PAS pickups and brake switch inputs are small and black. KT calls these M plug. Others are bigger and black, KT calls these WP plug.
Some controllers require a display to operate, some will operate with only a door switch input. i pick up the door switch power feed off the alarm power plug. I use a toggle switch in a pill bottle instead of installing a book compartment for a scooter with a door switch on my bicycle. If a display is required, be sure to buy one with the controller. Even if the connector matches, IMHO the software revision is applicable only to controllers made at the same time.
You should probably look to mounting the controller some other location where it does not get as much rain damage. Or mount a shelf over it. I use clear polycarbonate or acrylic sheet for such shelves. Use safety glasses when using power tools like saws & drills. I have such shelves over the taillights on my bike, as rain can damage those, also.
Replacement controllers especially ones made for scooters can have reverse rotation. First cut, reverse two motor phase wires. If it then runs badly in the right direction but groans above 5 mph, reverse two pins in the hall effect connector. This is more securely done by popping pins in the white square connector, instead of cutting the cable and reversing wires out in the middle of the air. Blue yellow green, you can swap two. Red & black you leave alone. Many controllers have a "learning" pair of wires that can be plugged together briefly to reverse rotation. If you use that, every time the battery is disconnected the direction has to be learned again. I swap wires instead, that is permanent.

 

[cwc]

Thanks for the response and all the info.
The controller that I referred to in my first post is from Totem so I'm hopeful the connectors will be correct.
I think that debris is from the inside of the large black electrolytic cap. One of it's leads is completely gone leading me to believe there was a lot of current flow at some time.
I'm now in contact with Totem Support to get some more info so I can check the hall sensors and other parts to see if they were damaged.

What is KT? Is it a source of information that I should be looking at?

 

[indianajo]

Lots of people like the KT controller. I mostly have been buying generic controllers made for scooters, since ebay prioritizes lower price products, even if they are shipped from 6000 miles away. I have never had a name for the black connectors, until the KT datasheet came with a new controller Saturday. You can only buy these black sensor+control connectors in lots of 100000 from alibaba etc. You have to have an air stamping machine to install those. The white square connectors, I have found a kit on ebay under the name "electric bicycle scooter connectors". Has replacement pins that can be soldered. There is a tang to push the pins out, which can be re-bent to push them back in again.
I have never had a hall effect sensor in the motor fail. I have had the sensor in the throttle get drowned out by the rain. I now wrap the throttle in a plastic bag when I ride in the rain.
Cheap-*** electrolytic capacitors are the bane all bike controllers. I have never disassembled one from Bosch or Shimano. In my first controller I replaced the garbage 470 uf capacitors with Panasonic or nichicon, which stopped the big spark, that always happens when you replug the DC power after it has been disconnected a minute. Good capacitors won't leak down for an hour or more.